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Finding the Fourth Proportional to 87.71, 121.60 and 83.09

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Solution

The fourth proportional to 87.71, 121.60 and 83.09 is: 115.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    87.71 : 121.60 = 83.09 : x
  2. Step 2: Convert to fraction form
    87.71/121.60 = 83.09/x
  3. Step 3: Cross multiply
    87.71x = 121.60 × 83.09
  4. Step 4: Simplify right side
    87.71x = 10,103.84
  5. Step 5: Solve for x
    x = 10,103.84/87.71
  6. Step 6: Final answer
    x = 115.20

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Why These Related Problems?

These problems maintain the same ratio (1.39) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.